In collaboration with M. Montal, UCSD, we have been investigating peptides with sequences corresponding the helical regions of large membrane embedded receptors, including the acetylcholine receptor, glycine receptor, and the NMDA receptor. The research on the NMDA Receptor is also in collaboration with M. Maccecchini of Symphony Pharmaceuticals. 20-25 residue peptides corresponding to the M2 segment apparently aggregate in membranes so that they function as channels. We have synthesized and expressed these peptides, and labeled them with stable isotopes, for NMR studies. The solid-state NMR studies show the trans-membrane orientation of the helices of these peptides. The uniformly labeled peptides in oriented bilayers are among the first targets for the multidimensional experiments we are developing for both increasing spectroscopic resolution and structure determination.